Grinding of gear-wheel teeth



April 24, 1928.

/NVCN TDR April 24, 1926.

H. H. ASBRIDGE GRINDING OF GEAR WHEEL TEETH Filed June 1l. 1926 3 Sheets-Sheet 2 HJIIMHM Il :s sheets-snee*L 3 Filed June 11. l192e H H ASBRIDGE GRINDING OF GEAR WHEEL TEETH April 24, 1928.

Patented Apr. 24, 1928'.

Partnr om @maar HALES assumes, er nsn'reN-oNirrEn'sln,ENGLAND; .friser'cilort"roz fri-IE @Hummm mncmmnmeer. eoxrmr maxim, or BMADHEATH, 'NEARMM- y OHESTER; ENGLAND.

.nppiieanqn me@ .im i1, mislead-.r9.2 115,400, amr *inn Great Britain" november- 24, n '1995.

- ,The problem of. grinding the. faces of gear Wheel teeth for the'purp'oe 0f imparting .to them`y accurately a .predetermined form,l by 'methods .involving the of the -Whol Arelativeiy to thefiat suriiaiceof .1a revolving grinding d-ise,..is one which..has henattkedfn a number ofways. i y.For .the purpose of .elucidating Vmyxliresgj ent inVentonI-willrefer to three known methods of procedure, all of them having this ingeommon, that during .the grinding 'Qperation, the wheel Ais reciprocated V4rela tvelyto the Agrinding disc by lmeans .of4 a slide', .and during recprocation has. imparted to it .an angularfmotionaboutitsaxis.

The method described .by Noyes in his British Patentv specification No. .f 107 ,608 is characterized in this that a templet or cam corresponding in Shaper-,to one face'ofthe' tooth is secured tothe spindle carryingthe y'srheeltov be Yground and arrangeazlto1 bear againsta `fixed abutment. In one direction of motion( )ithey slide vcarryingthejwheel the latter is rocked 4in .One directionby the f. interactionofjthe vtemplet v and abutment,

During the reverse motion ofthe slide the Wheel is, roked :in .the other directionl by a springwhich .keeps theY terziqnetL in contact with. theabutment. l

Thev second meth,

L is.' that'. by Boella in his British specification No.'l59, 50,3. Bolilla .mounted on the spindle-canyllg the Wheel t0= be. gro-und an-.-accurately shaped master or pattern Wheel ofi-the same size engaging afxed rack ,so1that recipro- Ctionof theiwh-eel by the side was., ,HGCQHF panied byan angular metionof-thewheel about. its.v airis. 'De lavoid slaeknessembank lashbetween.. the, master wheel .f and g they rack one tooth onfthe. rack was made ree and was pressecin. thedrectomo al1- diwentf fixed toothby means-oil' aspiring. Y ,y

The. thirdmethod. is that. otThe` Bradner Qmpeny',{described im theirA British; specification. No.'1,9503811l In tine-method. a double.. aetingeam fixed` v.orrthe spindlel r carrying the wheel, to'bet ground, is. located b.et-ineenA a' pair ,of fixed, abutmenits se? theta.

during: thek r'eciprocation. o! slide. `earry-- ing th. wheel. positiveangularf motions...are

imprtedito the Wheel about its axisiniboth directions of movement. I Y j Y y of the -metl-rods Aabove described though possessing certain `features in -oommon are, distinguished by the other lfeatures above mentioned, and iepresent diiferent a'ty tempts to overcome the wellknown mechanicalfydicul-t-ies yassoci-ated with the problem under consideration.

Y. Myexperience in the construction 'of .gear grinding machines leads me tothe 'conclue sion-that the methdin whi-chva templet act'-y ing one single fixed abuttnentrfor producing angular motion ofthe Wheel in oneV direction .and lfa springfor` producing the opposlte angular motion contains', the maxi@ f mum of advantages, but in the form pro' posed by Noyes isinconvenient, and,is.'n

deed, impracticable .where a rapid rateof working is re'quiredi--y The diiculty is occa-l sioned by the fact that a large angular move-y ment of the cam isnecessary (usuallyv about 1209), and .this'ne'cessitates correspondingly ,i i

spring, with the result that breakage of the spring -and other difficulties are liable f to Vlarge"c()In'pressio`ns lornextensions. of'the occur. Further in Vorder that` they templet' shall be kept at all timesv in contact with the abutment when operating at high speeds the strength. of zthe spring must ,be such that other complications are introduced. n The disadvantages of the spring method proposed, by Noyes .have been obvia-ted inthe Boelie and The:V LeesA yBradn'er" Company methods .by the elimination of the spring but not'withoutincirrring difficulties.'y Y 1 The object of .the present -invention is to provide a. machine inY which the spring-Withl its? advantages aire retained andilts' disadvantageslareeliminated. Stated otherwise, the

et my inyentionis to provide a mecha'- nismin .which the angular motion of the Wheel-.isobtaifned in the one direction by. the interaetionroi artempletA and fi-:re'df'a'birt` ment, andain-fthe other direction by a spring the movementfof which is less than', and may -bemuch less than, that corres'pending` tothe movement .of the; templet. H f

Briefly, the invention enn'iprisesY'theV mount# fing, fen. the spring ons; a-f kmovable carrier the* movements of which are coordinated with chine frame.

opposite direction during the return stroke those of the slide carrying the toothed wheel. In particular the invention comprises the mechanical arrangements hereinafter described.

In the three accompanyingsheets of eX- planatory drawings I Figure l is a diagram showing schematically one manner of carrying my invention into effect.

Figures 2 and 3 are side and front elvevations showing a. portion of a gear grind ing machine embodying the mechanism illustrated in Figure 1. l

Referring to Figure l, the toothed wheel a to be ground is secured to a spindle b which is carried on a slide c capableof reciprocating on a guide d. The grinding disc is indicated by e. This has a flat upper face on which eachv tooth face rolls in turn. The discrevolves about an axis f. As before; the rolling of the toothed wheel isobtained `by a combined reciprocatory movement of the slide c and an angular movement about the axis o'l the spindle Z). The angular movement in one direction is obtained by `a suitably shaped templet g which is secured to the spindle ZJ and vwhich makes contact at its periphery with an abutment roller Zt fixed on any convenient stationary part oi the ma- The angular movement in the of the slide is obtained by the spring z' which is arranged to operate in the follow ing manner. On the spindle Z9 is secured a toothed wheel y', preferably of twice the diameter of the wheel being ground. This engages with a rack k slidably mounted on a slide Z. The spring 71 is carried on the slide and is so arranged in conjunction with the slide and the rack that movement of the 'rack relatively to the slide in one direction is resisted by the spring. The slide Z is connected to the main slide c in any convenient manner such as by means ofi a lever u and links y so that they receive equal but opposite movements.

The spring 1.' is always under suitable compression. Starting from the position shown in Figure l, the slide o moves upwards and during this movement the interaction of the templet g and its abutment Zt causes the toothed wheel a to turn through the required angular distance relatively to the disc e. At the endy of `this movement the wheel is actually carried by the slide, clear of the disc to allow the wheel to be moved about its axis relatively to the templetfor,

the purpose of bringing a face of the next tooth into action, but this operation can be disregarded for the present. During the upward movement of the slideV c, the slide Z' moves downward, carrying the spring with it. yAlso the rack 7c moves downward' by reason of itsengagement with the toothed wheel Any relative movement between the parts /c and Z, is accommodated bythe spring. During the downward motion of the slide c (accompanied by an upward movement of the slide Z) the templet g is held "in contactwith the roller 'Zt by the spring acting through the rack Z0 and wheel Usually the variation in length of the `spring during the cycle of operations is small, and neveris it large 4in comparison with the angular movement oi the templet.

`The mounting of the spring on` a movable junction with a lever 'm carriedv on the slide,

Z; The slides c and Z are coupled by a Icentra-lly pivoted and equal armed lever .a mounted at the upper end of the fra-me or' standard of the machine. Reciprocation of the slide cis eii'ected by a connecting rod o actuated by a crank'v p., Therroller abutment k is mounted adjustably on the machine standard as shown.

As already stated, the slide Vc is givenl a movement in excess of that required for ac@ tual grindingv in order thatv during each cycle the wheelk may be carried `clear of the grinding disc for indexing-purposes, that to say for intermittently bringing anotherA tooth face into position for grmdmg. The necessary rotation of the spindle relatively to the templet during indexing is effected by any suitable means, and to avoid complication such means have been omitted from the drawings.

Having thus described my inventionwhat I claim as new and desire tov secure by Letters Patent is f -1. In a gear rcutting machine, a grinding disc having a flat face, a'templet andl sta-Y for co-ordinating the movements of the carrier with thoseof va member .carrying the toothed wheel, substantially as described.

2. In gear grinding machines of the'kind i specified, the combination comprising a pair of slides, means for producing opposite rel' ciprocatory movements of the slides, a work spindle on one of the slides,ja templet on the spindle, an abutment carried on the xed frame of the machine in Contact with the templet, a toothed Wheel on the spindle, a rack carried by the other slide 'and en aged by the said toothed Wheel, the rack eing movable relatively to its slideand a' spring the action and reaction of which aretaken by the vrack and its slide respectively, sub-v stantially as described. y

3. In gear grinding machines of thekind specified, the combination comprising a pair of slides, means for producing opposite reciprocatory movements of the slides, awork lmovable relatively to its .-slide, a leversu porting the rack and pivoted on the sli e carrying the rack, Aand a spring yacting on the lever,'si1bstantially as described. e

In testimony whereof [I have signedvmy 25' name'to this specification.

HARRY HALES ASBRIDGE; 

